AS2 - Set Mask and scale

[RESlyder]

Hey all,

I am working on a small program that allows the user to draw a box (doc_mask) over an image (in this case a document). The mask is then set and I change the scale of the mask and the image it is masking. However once it scales it doesn't match up with what the user originally highlighted. I am attaching my fla in hope that maybe someone can help me out!

Here is a link to the swf so you can see what I mean:
http://carolynwebster.com/highlighter/HL_8.swf

Thanks in advance!